1. Field
The present invention relates to a content distribution technology. In particular, it relates to a content distribution system, a content distribution method, a terminal apparatus in the content distribution system, and a recording medium on which a program is recorded, wherein a plurality of terminal apparatus are logically connected in multilayers in a hierarchical structure in a network, with a content distribution apparatus which stream-distributes content data as an apex, and the content data transmitted from the content distribution apparatus are sequentially stream-distributed by a relay function of the terminal apparatus from an upstream terminal apparatus to a downstream terminal apparatus in the hierarchical structure.
2. Description of the Related Art
In recent years, a content distribution service has been started which carries out a stream distribution of data of content (hereafter called “content data”), such as music, a movie, or a talk program, via a network such as the Internet. Herein, a stream distribution being a distribution method which distributes content data in a stream format which a client terminal apparatus (hereafter called simply a “terminal apparatus”) can stream-receive the content data, the terminal apparatus can reproduce the stream-distributed content data while receiving them. Also, as a stream distribution format, there is a broadcast format, wherein a content data distribution time is fixed, and an on-demand format, which stream-distributes content data to individual terminal apparatus in response to a request from the terminal apparatus.
A broadcast format content distribution service has, to date, principally been one which carries out a distribution of content directly from one content distribution apparatus to a plurality of terminal apparatus but, in recent years, a content distribution system has been proposed which can reduce a burden and a concentration of traffic, without increasing the content distribution apparatus, by using a relay of content data among the terminal apparatus, that is, a P2P communication format (for example, refer to Japanese Unexamined Patent Publication 2006-41784).
This content distribution system is one in which a plurality of terminal apparatus are logically connected in multilayers in a tree-shaped hierarchical structure, with a content distribution apparatus as an apex, and content data are sequentially distributed from the content distribution apparatus to a downstream terminal apparatus.
That is, the content data distributed from the content distribution apparatus are distributed to a terminal apparatus positioned on a topmost layer (a first layer), the terminal apparatus positioned on the topmost layer relays the content data distributed from the content distribution apparatus to a terminal apparatus positioned on a second layer, and the relay of the content data is carried out until they are distributed to a terminal apparatus positioned furthest downstream.